Regenerative repeater



FIG.

Hui

w. VT. REA 2,186,150

REGENERAT IVE REPEATER Jan. 9, 1940.

Filed March 3, 1938 A T TORNE V Patented Jan. 9, 1940 REGENERATIVE REPEATER Wilton T. Rea, Flushing, N. Y., assignor to Bell Telephone Laboratories, Incorporated, New York, N. Y., a corporation of New York Application March 3, 1938, Serial No. 193,643

3 Claims.

This invention relates to signaling systems and particularly to methods and means for repeating signal impulses.

An object of the invention is to provide means responsive to signals in the form of potential changes which will mechanically repeat signal impulses and at the same time correct mutilated impulses with regard to, their time elements. The invention will be understood by those skilled in the art when it is termed a mechanical regenerative repeater, by which is meant in general terms a repeater which, responding to an impulse, will mechanically lock in for the full duration of the impulse whether or not the impulse continues to last at full strength during such time. Thus when impulses are distorted by transmission sent over a line or affected in such a manner that they are received in mutilated form they may be mechanically corrected and retransmitted in perfect form as regards both their intensity and timing.

A further object of the invention is to control a mechanical regenerative repeater by means requiring a minimum of energy.

- A feature of the invention is the use of responding means having substantially no electrical impedance. By way of example such a device is shown as a crystal element interleaved with conducting elements in the manner of an electrical condenser and which will respond with great rapidity to a difl'erence in potential impressed on such conducting elements by a warping or bending action which is translated into a mechanical movement sufficient to close electrical contacts and move a stop pin to either side of a I Such a device requires for its locking cam. operation that amount of energy only which may be measured by the charge of the condenserlike conducting elements and since its response is due to the potential difference set up on said conducting elements it does not require a flow mechanical regenerative repeater shown at a cenchamcal details of the crystal relay forming the novel features of this invention.

The relayxconsists of two pieces I and 2' of Rochelle salt or piezoelectric body having similar properties and having conducting sheets 3, 4, and 5 facing'them with sheets 3 and .5 connected together so that a potential difference may be established between sheet 4 and sheets 3 and 5. The relay is rigidly mounted at its letthand end and carries a contact 6 at its right- 10 hand or free end which contact 6 may cooperate with the stationary contacts 1 and 8. There is also a pin 9 mounted on the free end of the crystals which will cooperate with the pin 10 on the pawl ll move the pin In to such a position that thepin 9 may move either above or below it. As the wheel l2 revolves and the pin It! moves out of the path of pin 9 the relay may be energized to move to either one position or the other and immediately'thereafter the pin IE will be moved to such a point that if the relay is asshown in Fig. 2, it will be mechanically locked to contact 1. If during the time that the pawl I l was riding on one of the cams l3 the relay was moved to its contact 8 then the pin l0 would, through cooperation with pin Q, hold the relay mechanically locked in this p0siti0n.- G

Let us assume that the contacts M are operated to send a series of signals. Some of these signals will be closed-circuit and some open-circuit signals'. When the circuit is closed, then current will flow through the winding of relay l5 and the upper winding of relay l6 and hold this relay to its right-hand or marking contact. I When the signals are open-circuit signals, thenthe armature of relay IE will be moved to its left-hand or spacing contact. Since the first signal in a train of permutation code signals is always a spacing signal, the relay Iii will .close the circuit from battery, its armature and lefthand or spacing contact, windingof magnet I! to positive battery l8. Magnet ll moves its armature out of the path of cam l9 and allows shaft 20 to be energized through the clutch 2| by the power source 22. As soon as the shaft 20 is moved off normal, contacts 23 will be closed and will remain closed until the shaft 20 has completed one revolution. During this'period, negative battery is connected through the contacts 23 to line 24 and thence through the lower winding of relay 25. This will keep relay 25 on its marking contact even though the circuit through its upper winding is open.

The relay 26 is a crystal relay such as that shown more in detail in Fig. 1. It is normally energized by potential from ground on its inner conducting surface to negative battery on its two outer conducting surfaces derived through the resistance 21 and marking contact of armature relay it. When the impulse being sent is a marking impulse, then the relay will be energized and will move its armature to its upper or marking contact and pin ii] will maintain it in this position mechanically for the full length of the impulse. When a spacing signal is sent, however, the potential diiference on the conducting sheets of this relay is removed and the relay moves its armature to its spacing contact so that pin ID will maintain it in this position. The wheel I2 and the earns 13 are so proportioned that the pawl M will be moved at the beginning of the properinterval for each of the usual seven impulses forming the train of a permutation code.

The movement of relay 26 opens and closes the circuit for relay 28 at the distant end so that relay 28 will be energized in accordance with the operation of the permutation code contacts I4.

Thus, if the station representedby contacts l4 and relay l5 transmits over a particularly long line or if there is any other effect present which would cause distortion of the signals received by relay IS the arrangement of the pins 9 and i0 for operating through the movement of the crystal relay 26 will correct the defect and send out toward. the right-hand distant end impulses of full strength and correct timing.

The operation in the reverse direction is of a similar nature and will not be further described.

What is claimed is:

l. A signal repeating device comprising a condenser type relay comprising crystal elements interleaved with conducting elements responsive only to potential changes and requiring for its operation only that amount of energy measured by the charging current of a small condenser, said relay being responsive to incoming signals and operating to transmit corresponding outgoing signals and mechanical timing means cooperating with said relay for locking the armature of said relay in either its operated or its released position after the response to each incomsignal for a period of time corresponding to the normal length of a signal whereby said trans mitted signals will be of normal length regardless of the distortion in length of said incoming signals.

2. A signal repeating device as claimed in claim 1 wherein said relay crystals consist of piezoelectrio material.

3. A signal repeating device as claimed in claim 1 wherein said relay crystals consist of Rochelle salt.

WILTON T. REA. 

